Thanks for the query.
She might be suffering from a mild fungal infection
It is called as P versicolor.
It is a common condition in children.
Dont worry just apply some anti fungal cream for month,
She should get relief from this.
Please meet a dermatologist
and discuss regarding this.
Let me know if you have any other doubt.
you can ask a direct question to me on this forum, following the below link.
Wishing you a good health.